In sentence-style capitalization, you capitalize only the first word of
the title or heading, plus any proper nouns, proper adjectives, and
terms that are always capitalized, such as some acronyms and
abbreviations. If the title includes a colon, capitalize the first word
that follows the colon, regardless of its part of speech.

If the heading includes text from a user interface, the capitalization
of that text must match the capitalization on the interface.

Examples

Preparing a cloud server to be a mail server

Can I buy extra IP addresses?

What are cloud servers?

What are the PHP configuration limits for Cloud Sites?

Install or upgrade PHP 5.3 for CentOS 5.x

How do I install my own PEAR module?

Ubuntu Hardy: Using mod_python to serve your application

I live outside the United States. Can I use my foreign credit card to
pay for my account?

Use the guidelines in this section to create effective and consistent titles
and headings. The following guidelines apply to all titles and headings;
special considerations for stand-alone articles, product guides, and tables,
figures, and examples follow this list.

Create succinct, meaningful, descriptive titles and headings, and place the
most important words first.

Ensure that each title and heading is unique within a given content set.

Include articles, prepositions, and punctuation as needed for clarity.
However, avoid using an article (a, an, or the) as the first word.

Avoid showing both an abbreviation and its spelled-out term in a title or
heading. To help control the length of titles and headings, show the
abbreviation in the title or heading and then define it in the first
paragraph of the text.

If you show a literal term (such as a command or option name) in a title or
heading, follow it with an appropriate noun.

Don't end a title or heading with a colon or period. If the title or heading
is in the form of a question, end it with a question mark.

Don't apply font treatments (bold, italics, or monospace) to text in a title
or heading.

Don't include trademark symbols in titles or headings. Show the symbol on the
first use of the trademark in text.

Avoid having only a single heading at any level (for example, a single
subsection in an article or section). If you find that you have a single
heading at any one level, consider whether you can reorganize the information
to either eliminate the heading or add a second one at that level.

Avoid having more than two levels of sections within an article or topic. If
you use more than two levels of sections, consider whether you can reorganize
to make the structure flatter.

Don’t "stack" titles or headings. That is, don’t immediately follow a title
or heading with another title or heading. Text should always intervene
between them. Ensure that such text is meaningful. If it is just filler text,
consider whether you can restructure the content.

Use a consistent grammatical structure for the titles and headings of
specific types of content:

In addition to the preceding guidelines, use the following guidelines when
creating titles and headings for stand-alone articles on the Support site or in
other collections of documentation:

Create article titles that don’t rely on body text or other titles for their
meaning (that are, in other words, independent of context). Users should be
able to tell from a title whether the information in the article is relevant
to their needs. Avoid ambiguous one-word titles, such as "Overview."

Don't number titles to indicate their placement in a series of articles.
Indicate the order of articles within the content of the article, referring
users to information that they should have read previously before reading the
current article. Use links to provide navigation to preceding and following
articles in the series.

Start with the highest level of heading that is approved for headings
(for example, h3), and do not skip heading levels.

In addition to the preceding guidelines, use the following guidelines when
creating titles and headings for sections in product guides:

If possible, limit titles and headings to 60 characters for legibility in the
TOC pane.

Consider that titles and headings are written within the context of the
content set in which they are presented. Therefore, you can usually omit
"context-setting" terms. For example, if the content set is about servers,
you can usually omit "for servers" from the title or heading.
(For example, "Attach a network to a server" can be shortened to
"Attach a network" with no loss of clarity.)

Don’t immediately follow a title or heading with another title or heading.
Instead, follow a title or heading with body text.

The body text must be independent from the title or heading. Don't use a title
or heading as an antecedent in the sentence that follows it. That is, be sure
to repeat the subject in the first sentence that follows the title or heading,
rather than using a pronoun that refers to the title or heading as its
antecedent.

Use

Don't use

Identify network interfaces on Linux

This article briefly describes how to identify which network interfaces
on a Linux server are associated with which IP addresses.